Another “way of knowing” is through reason and logic. In the theory of knowledge course, the term logic is defined as reasoning conducted or assessed according to strict principles of validity. These set of principles are often understood everywhere in the world, and as a result can be seen as a “universal language”. On the other hand, reason is a justification for an action or event. These two concepts are often interconnected as reason can be seen as the development of an argument, which is based on logic. There are two main forms of reasoning that are discussed in the theory of knowledge course, which are Deductive Reasoning and Inductive Reasoning.
Deductive reasoning is an argument that involves starting out with a theory or general statement, then moving towards a specific conclusion. Contrary to this, inductive reasoning takes a series of specific observations and tries to expand them into a more general statement.
Deductive Reasoning
Example: “I am a human, All humans are mortal, Therefore I am mortal”
Inductive Reasoning
Example: “In my life the sun has risen everyday for 17556 consecutive times, therefore it will rise again tomorrow.”
In the theory of knowledge course, both of these approaches are very different from each other. In addition, it is important to understand that both inductive and deductive reasoning can end up in providing false statements. These false statements, and/or theories are often not logical.
Ian Barton's Theory of Knowledge 